JDE Job Scheduler again

Need to ask this question again...

Correct me if I am wrong – the Oracle/JDE scheduler only works off of a pre-established time schedule in order to submit a job.
There isn’t a means for the scheduler to get triggered by some external event – is this correct?

Is there a way to manually start/stop the scheduler in JDE other than doing it via OMW?

I had previously asked this:

Is there any means to make use of an external event controlled by some other system that would then start the scheduler to run the job(s)?

Perhaps we can always have the scheduler server stopped and some external event can then start the scheduler server which would then determine if the job is late, at which point it would begin its execution?